SOLUTION: The length of a rectangle is twice the width. The perimeter is 84cm more than the width. Make a diagram and find the rectangle's dimensions.

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Question 162180: The length of a rectangle is twice the width. The perimeter is 84cm more than the width. Make a diagram and find the rectangle's dimensions.
Answer by KnightOwlTutor(293) About Me  (Show Source):
You can put this solution on YOUR website!
We know that the equation for determining the perimeter of a rectangle is P=L+w+L=W P=2L+2W
We know that L=2W
We know that the perimeter is=W+84cm
W+84=2(2W)+2W
w+84=4W+2W
W+84=6W
Subtract w from both sides
84=5W
Divide both sides by 5
W=16.8
L=33.6
2(16.8)+2(33.6)=33.6+67.2=100.8
Let's double check our answer
We know that the perimeter was 84 more than the width

100.8-84=16.8